Strong, independent, sexy, attractive woman who knows what she wants and how to get it.

Used by men, 'Sexy bitch neena' is not a derogatory term. A man who uses it is admitting that he is sexually attracted but probably not good enough for her; that he would feel vulnerable in her presence because he won't be able to control her. So there may be a tinge of resentment, especially when used by a woman to describe another because she cannot compete.